The Analytical Core will serve as a collection and distribution point for blood and fecal samples, DNA, colorectal adenoma tissue blocks, and rectal mucosal samples. It will provide a resource and service for carrying our the laboratory analyses proposed in this application in support of the clinical trials. The Core will develop appropriate sample collection, tracking, storage, and preparation procedures for all human material collected during the course of this proposal. It will develop and optimize methods for measuring the secondary laboratory directed research endpoints to be used in evaluating the various trials to be conducted by the individual Projects in this proposal. The Analytical Core will be responsible for the collection, logging, processing, distribution, and tracking of all tissues and samples. Endpoints to be analyzed by the Analytical Core will include blood levels of treatment drug and fecal primary and secondary bile acid concentrations. In addition, the core will be responsible for analyzing genetic polymorphisms, molecular genetic and epigenetic markers (CIMP status, Ki-ras, p53, APC), and CIMP and COX expression in DNA, archival tissue blocks and rectal mucosal biopsies. The Analytical Core will analyze nuclear chromatin texture alterations in rectal biopsies and cell proliferation measured by labeling indices using PCNA as well as apoptosis by in situ TUNEL and morphology in archival colorectal adenomas. The Analytical Core will oversee and coordinate the collection and processing of all samples related to this Program Project at the various participating hospitals and clinics. In addition, the Analytical Core will be responsible for the training of personnel involved in the collection and processing of study samples. It will perform actual assays and will work closely with the Biometry ore to provide data for reporting and interpretation. Quality assurance and quality control procedures will continue to be developed by the Analytical Core which will be supervised by the Biometry Core for sample acquisition, processing, and analysis procedures included in each of the clinical projects.